U.S. Pat. No. 6,509,733B2 discloses a fluid pressure cylinder including a position sensor that detects a relative position of a piston rod with respect to a cylinder tube.
The position sensor of this fluid pressure cylinder has a sensor body fixed to the cylinder tube and a sensor rod extending along an axial direction of the cylinder tube from the sensor body. In the piston rod, a hole that extends along an axial direction of the piston rod is formed, and the sensor rod is movably inserted in that hole.